feature request: Swap between light/dark mode

[klin39]

Inspiration: https://twitter.com/jsngr/status/1197981570466033665

Several libraries include the keywords "dark" or "light" in the symbol structure, and it would be really handy to be able to select a layer/text style, symbol, or artboard and have it automatically toggle between light and dark.

Would also be awesome if there was a way to configure a custom word to look for, for example: "☀️" or "🌑"

Thank you!
Kevin Lin